what happen if use not original charger?

They should 'work'... but you may experience charging or battery issues.

Use only Apple approved charging devices and systems. Some 3rd party cables aren't safe and can harm your iPhone.

Hi

When buying electronic accessories for your iPhone, ensure that they are either genuine Apple products or that they have been certified as Made for iPhone under the MFi program. Certified items come with the "Made for iPhone" logo on them and/or on their packaging.

Genuine Apple Lightning to USB cables have certain text and a serial number printed on them.

Using uncertified or counterfeit accessories may damage your iPhone and/or adversely affect operation. Apple's warranty does not cover damage caused by use with a third party product that does not meet Apple's specifications.

Using counterfeit or uncertified third-party cables, for example, can cause issues including:

• Your iPhone may not charge properly.
• Your iPhone may not sync properly.
• Your iPhone could become damaged.
• The cable may become more easily damaged.

Apple also recommends using the Apple USB Power Adapter that came with your iPhone (or another compatible Apple power adapter).

More information:

About iPhone, iPad, and iPod accessories - Apple Support

Identify counterfeit or uncertified Lightning connector accessories - Apple Support

Third party chargers are not compatible with Apple iOS mobiles , the charger will not charge completely the phone or cable of the charger will heat up & get damaged up itself .

And regarding the phone I am not sure ( could damage ) , but we must not use third party chargers , it is alway wiser to purchase the charger from Apple authorised Apple Store .

I personally have experienced the same issue , purchased a duplicate charger , it worked for few days and created issues , so from that day onwards a big " NO " to a third party charger .

Thanks !